Various methods are proposed for manufacturing optical fiber glass in a continuous process. The method proposed in U.S. Pat. No. 3,957,474 involves the deposition of the glass forming ingredients on a heated mandrel to form a fiber optic preform. The solid preform is then placed in a drawing tower and is heated and drawn into an optical fiber.
The method described in U.S. Pat. No. 3,614,197 uses a multi-stepped funnel-shaped heating vessel to form a solid glass rod which is subsequently heated and drawn into an optical fiber.
U.S. Pat. application Ser. No. 751,282 filed Dec. 16, 1976 now U.S. Pat. No. 4,065,280 improves over the heated mandrel and multiple crucible process by providing for the continuous fiber manufacture without the need for first forming a fiber optic preform.
This invention improves over prior art continuous fiber drawing processes by the use of plasma torches and a heated rotatable mandrel to greatly increase the speed of the fiber deposition and drawing processes.